I have a small Waeco fridge in my truck & keep it stocked each week with stuff like milk, juice, coffee creamer, strawberry jam, yogurt & a few other things that need to be kept cool. I always have crackers on hand, along with bread, tuna and peanut butter & things to make sandwiches. I’ve tried SPAM on a couple occasions, but it doesn’t always set well with me.
I use a small, 12-volt coffee maker on mornings when I’m not parked at a truck stop to get coffee in the store.
There’s usually a flat of bottled water in my truck, as well as a couple gallons of drinking water I can use for washing up or making coffee, etc. I always stock up on this stuff at Walmart because it’s less than half the cost most truck stops charge.